The document EP-B-0 177 521 discloses a filter element whose substantially inherently stable, permeably porous shaped body is made of fine-grained polyethylene with a higher molecular weight, and polyethylene which is fine-grained in the initial state with a lower molecular weight, these polyethylene components being combined into the shaped body by the action of heat, and a surface-pore coating of fine-grained polytetrafluoroethylene being provided. In actually produced filter elements of this kind the higher-molecular polyethylene has a molecular weight of more than 10.sup.6. Due to the surface-pore coating, the filter element can filter on the principle of surface filtration. Even fine and extremely fine particles of the medium to be filtered are already held on the afflux surface of the filter element and can be cleaned off of this surface very easily, for example by the backflow principle.
These filter elements were hitherto produced using an ultrahigh-molecular polyethylene starting material, in which just under 10% of grains are larger than 250 microns and smaller than or equal to 63 microns. These filter elements are used quite successfully in practice. However the invention achieves a further improvement in known filter elements.
It is an object of the invention to solve the technical problem of developing a permeably porous filter element having a substantially inherently stable shaped body made substantially of polyethylene and bearing a fine-pored coating on its afflux surface, so as to reduce flow resistance and improve the formation of the coating.